This invention relates to lubricants for and methods of processing synthetic fibers.
During the spinning process of synthetic fibers such as polyamide and polyester fibers, it is important to prevent generation of fuzz and occurrence of yarn breakages. Since synthetic fibers for industrial materials such as tire cords, seat belts and air bags are produced under severe conditions of high temperature and high contact pressure and are likely to generate fuzz and yarn breakages, it is particularly important with such fibers to prevent generation of fuzz and occurrence of yarn breakages. Agents for lubricating such synthetic fibers (herein referred to simply as the lubricants) are therefore required to be capable of providing sufficient lubricity even to synthetic fibers adapted to undergo a spinning process under a severe condition of high temperature and high contact pressure. This invention relates to lubricating agents which can respond to such a demand and also to methods of processing synthetic fibers.
Examples of prior art lubricant proposed for providing lubricity even to synthetic fibers adapted to undergo a spinning process under such severe temperature and pressure conditions include salts of phosphoric acid ester such as (1) salts of phosphoric acid ester derived from alkylene oxide adduct of branched alcohol having a side chain at .beta. (Japanese Patent Publication Tokkai 62-69881), (2) salts of phosphoric acid ester derived from higher alcohol having an alkyl group with 30-50 carbon atoms or alkylene oxide adduct of such higher alcohol (Japanese Patent Publication Tokkai 3-871), and (3) amine salts of phosphoric acid ester obtained by neutralizing acidic phosphoric acid ester derived from ethylene oxide adduct of higher alcohol by using aliphatic amine or ethylene oxide adduct of aliphatic amine (Japanese Patent Publications Tokkai 6-346368 and 7-166433). Also being proposed are methods of using high molecular compounds such as (4) polyester obtained from polyhydroxy compound and dibasic acid having both its ends closed with aliphatic alcohol, its alkylene oxide adduct or aliphatic carboxylic acid (Japanese Patent Publications Tokkai 3-871 and 5-339875), (5) polyoxyalkyleneglycol with average molecular weight greater than 1000 (Japanese Patent Publication Tokkai 6-158538), and (6) alkylene oxide polymers of alkylamine or dialkylamine with average molecular weight 1000-20000 (Japanese Patent Publication Tokkai 6-228885). These prior art lubricants could not provide a high level of lubricity to synthetic fibers, however, and lubricity could be provided only to a very unsatisfactory level in the case of synthetic fibers as industrial materials adapted to be processed under a condition of high temperature and high contact pressure. Thus, generation of fuzz and occurrence of yarn breakage could not be adequately prevented by prior art lubricants.